Cleaning granular particles requires separating the desired end product from the variety of component parts, contained in the material. For example, grains when harvested are often covered with dirt and other materials. Silica sand, used as a molding media in the foundry industry becomes contaminanted with additives; and minerals, such as clay feldspar are mixed with a variety of other elements. Further, the outer surface of some grains and nuts, such as rice and pecans, requires removal. To use or reclaim the desired end product, a grinding process is utilized.
I have invented a machine and process for grinding particulate materials by introducing the material to be to be processed between two flexible continuously moveable belts. The belts circumscribe the granular particles allowing the material to be rotated and transported alongthe lengths of the belts. No spillage occurs and sufficient tension may be applied to each belt to result in the rotating action which dislodges the particles from the predetermined end product.
Generally, the process for obtaining or reclaiming the desired end product involves complex, metal machinery including mechanical grinders, rotary drums, disks, screw mechanisms, screens, metal scrub brushes and the like. Often times, water and/or chemicals are used as part of the recovery process. The force exerted by these processes results in damage to the product to be recovered, resulting in less than optimal recovery, and costly damage to the equipment as the metal parts are worn by friction. The addition of water to the process requires availability of a sufficient water supply to maintain the process and also requires a drying process before the desired product can be used. Chemical cleaning, such as is common in the foundry industry results in less than optimal recovery, approximately fifty percent.
All of these problems are resolved by the claimed invention. The rotating action necessary to grind the granular particles occurs in a cavity between the conveyor belts. The granular particles do not come in contact with any other surfaces, such as metal, during the rotating action. The claimed invention provides a high yield of separation of materials which in turn provides a high yield of the desired end product, resulting in almost complete recovery of the desired product. Very little damage is done to the granular particles because the materials only comes in contact with the non-metal surfaces, such as rubber, and is not crushed against metal surfaces.
It is a primary object of this invention to provide a machine and process for grinding granular material using conveyor belts.
It is a further object of this invention to provide a machine and process which can grind granular material by a cold and dry process with use of relatively low amounts of energy.
It is a still further object of this invention to minimize damage to the desired end product.
It is yet another object of this invention to provide an efficient low initial cost and low maintainance cost system for attaining a high yield end product which overcomes the deficiencies of the present systems.